Sun Java System Access Manager 7.1 Performance Tuning and Troubleshooting Guide

Troubleshoot the Problems You Find

A common problem is that when two Access Manager instances are both running, you see not only login and logout requests, but session requests as well. The test results may look similar to this:

    3159   31590  277992
       0       0       0
    5096   50960  486676
       0       0       0
       0       0       0
    1305   13050  127890
    3085   30850  280735
   12664  126621 1174471 a

In this example, for each logout request, there are now extra session and notification requests. The total number of requests does add up. This means there are no other unexpected requests. The reason for the session request is that the sticky load balancing is not working properly. A user logged in on one Access Manager instance, then is sent to another AM instance for logout. The second Access Manager instance must generate an extra session request to the originating AM instance to perform the request. The extra session request increases the system workload and reduces the maximum throughput the system can provide. In this case, the two Access Manager instances cannot double the throughout of the single Access Manager throughput. Instead, there is a mere 20% increase. You can address the problem at this point by reconfiguring the load balancer. This is an example of a problem should have been caught during modular verification steps in the system construction phase.